From: Bossart, Nathan <bossartn@amazon.com>
To: Andres Freund <andres@anarazel.de>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: 蔡梦娟(玊于) <mengjuan.cmj@alibaba-inc.com>
Cc: Jakub Wartak <Jakub.Wartak@tomtom.com>
Subject: Re: prevent immature WAL streaming
Date: Thu, 2 Sep 2021 00:04:17 +0000
Message-ID: <83C102B9-991B-417D-80C0-193AC3887C0B@amazon.com> (raw)
In-Reply-To: <20210901170052.4iz3iilihqkad4ui@alap3.anarazel.de>
References: <20210831042949.52eqp5xwbxgrfank@alap3.anarazel.de>
<202108311356.sl33wcpcz5x6@alvherre.pgsql>
<20210831155333.2vv2zdf7v4nhh2m2@alap3.anarazel.de>
<bb15b918-6dad-b01d-23b9-17b5dfa7e6a2@oss.nttdata.com>
<20210901031524.mdo6aayalmd5jxly@alap3.anarazel.de>
<8acc33c8-fb75-fda4-8909-50d21f9e8725@oss.nttdata.com>
<20210901170052.4iz3iilihqkad4ui@alap3.anarazel.de>
On 9/1/21, 10:06 AM, "Andres Freund" <andres@anarazel.de> wrote:
> On 2021-09-01 15:01:43 +0900, Fujii Masao wrote:
>> Thanks for clarifying that! Unless I misunderstand that, when recovery ends
>> at a partially-flushed segment-spanning record, it sets
>> XLP_FIRST_IS_ABORTED_PARTIAL in the next segment before starting writing
>> new WAL data there. Therefore XLP_FIRST_IS_CONTRECORD or
>> XLP_FIRST_IS_ABORTED_PARTIAL must be set in the next segment following
>> a partially-flushed segment-spanning record. If none of them is set,
>> the validation code in recovery should report an error.
>
> Right. With the small addition that I think we shouldn't just do this for
> segment spanning records, but for all records spanning pages.
This approach seems promising. I like that it avoids adding extra
work in the hot path for writing WAL. I'm assuming it won't be back-
patchable, though.
Nathan
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To: pgsql-hackers@postgresql.org
Cc: bossartn@amazon.com, andres@anarazel.de, masao.fujii@oss.nttdata.com, alvherre@alvh.no-ip.org, pgsql-hackers@lists.postgresql.org, horikyota.ntt@gmail.com, mengjuan.cmj@alibaba-inc.com, Jakub.Wartak@tomtom.com
Subject: Re: prevent immature WAL streaming
In-Reply-To: <83C102B9-991B-417D-80C0-193AC3887C0B@amazon.com>
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